Detectors for detecting electromagnetic radiation such as x-rays or visible light are used in many applications, including medical and security imaging, astrophysics and cameras. One example of a radiation detector is disclosed in U.S. Pat. No. 7,968,853. The so-called ‘double decker detector’ described therein comprises a two-dimensional array of stacked scintillators facing an x-ray source. Active areas of photodiodes are optically coupled to the stacked scintillators. The photodiodes and scintillators are oriented transversely with respect to a substrate, which usually is in connection with application-specific integrated circuits (ASICs) and output electronics.
The photodiodes are supported by the substrate through electrically conducting connections. This requires a high precision combined with sufficient mechanical strength. Known connections comprise a metallic spike (usually a series of stacked stud bumps) attached to the photodiode which penetrates into a deposit of conductive adhesive on the substrate. However, it has proven to be a challenge to construct sufficiently accurate and reliable connections that are mechanically strong and/or without poor contacts, opens and shorts using this construction method, while maintaining sufficient flexibility to withstand mechanical, thermal and rotational stresses.
These issues are also often encountered with other (micro)-electronic or (micro)-mechanic applications wherein pieces need to be reliable fixed in a transverse orientation with respect to each other.